The brain controls and monitors all body function. It communicates with the rest of the body by way of the spinal cord and the nerves that exit the spinal cord.  The spinal cord is housed by the spinal column made up of 24 vertebrae  for protection.  This is much like an information highway with many exits all controlled by a central processing center.  At every level of the spine nerves exit to supply various end organs. 

The spinal column forms joints between each two vertebrae.  Within each joint are tiny structures called mechanoreceptors.  They are part of the nervous system.  When we move they respond to motion and fire off information to the brain.  This activates and stimulates the brain making it healthy. 

Sometimes joints become locked or fixated.  When this happens there is no motion in those receptors and they go off-line so to speak.  A decrease in motion from enough of these joints for a long enough period of time will cause a gradual decrease in brain and body function.  This could take place over decades.  Eventually the joint itself and the soft tissues around it degenerates because it receives no information back from the brain.  The brain receives less input and therefore output of information decreases affecting the whole body.  So there is both a local and global degeneration.

In chiropractic we say dis-ease leads to disease.

The chiropractic adjustment does three main things:

1) Restores range of motion to the joint
2)Fires a barrage of info into those receptors
3) Causes the surrounding muscles to relax

All of this restores and increases function by increasing brain activity.